Search Publications
An accretion disc origin for the `X-ray broad-line region' in 1H0707-495
Fabian, A. C.; Blustin, A. J.
We use a 380-ks X-ray Multi-Mirror Mission-Newton (XMM-Newton) high-resolution Reflection Grating Spectrometer (RGS) spectrum to look for narrow spectral features from the nuclear environment of 1H0707-495. We do not find any evidence of a line-of-sight ionized wind (warm absorber). We do, however, detect broad emission lines, of width ~5000 kms
Scandium and chromium in the strontium filament in the Homunculus of ηCarinae
Gull, T. R.; Bautista, M. A.; Martínez, M. +4 more
We continue a systematic study of chemical abundances of the strontium filament found in the ejecta of ηCarinae. To this end we interpret the emission spectrum of ScII and CrII using multilevel non-local thermodynamic equilibrium models. Since the atomic data for these ions were previously unavailable, we carry out ab initio calculations of radiat…
The aperiodic broad-band X-ray variability of Cygnus X-3
Axelsson, Magnus; Larsson, Stefan; Hjalmarsdotter, Linnea
We study the soft X-ray variability of Cygnus X-3. By combining data from the All-Sky Monitor and Proportional Counter Array instruments on the RXTE satellite with EXOSAT/Medium Energy (ME) detector observations, we are able to analyse the power density spectrum (PDS) of the source from 10-9 to 0.1 Hz, thus covering time-scales from sec…
IGR J16351-5806: another close by Compton-thick AGN
de Rosa, A.; Bird, A. J.; Malizia, A. +2 more
IGR J16351-5806 has been associated with the Seyfert 2 galaxy ESO 137-G34, having been first reported as a high energy emitter in the third INTEGRAL/Imager on Board the INTEGRAL Satellite survey. Using a new diagnostic tool based on X-ray column density measurements versus softness ratios (F2-10keV/F20-100keV), we have previo…
Predicted γ-ray image of SN 1006 due to inverse Compton emission
Miceli, M.; Bocchino, F.; Orlando, S. +5 more
We propose a method to synthesize the inverse Compton (IC) γ-ray image of a supernova remnant starting from the radio (or hard X-ray) map and using results of the spatially resolved X-ray spectral analysis. The method is successfully applied to SN 1006. We found that synthesized IC γ-ray images of SN 1006 show morphology in nice agreement with tha…
The globular cluster NGC 6642: evidence for a depleted mass function in a very old cluster
Santiago, B. X.; Balbinot, E.; Bonatto, C. +1 more
We present photometry for the globular cluster NGC6642 using the F606W and F814W filters with the Advanced Camera for Surveys in the Wide Field Channel (ACS/WFC) third generation camera on board of Hubble Space Telescope. The colour-magnitude diagram shows sources reaching ~6mag below the turn-off in mF606W. A theoretical isochrone fitt…
SDSS absolute magnitudes for thin-disc stars based on trigonometric parallaxes
Cabrera-Lavers, A.; Bilir, S.; Yaz, E. +3 more
We present a new luminosity-colour relation based on trigonometric parallaxes for thin-disc main-sequence stars in Sloan Digital Sky Survey (SDSS) photometry. We matched stars from the newly reduced Hipparcos catalogue with the ones taken from Two-Micron All-Sky Survey (2MASS) All-Sky Catalogue of Point Sources, and applied a series of constraints…
Groups of galaxies in AEGIS: the 200-ks Chandra extended X-ray source catalogue
Nandra, Kirpal; Davis, Marc; Willmer, Christopher N. A. +6 more
We present the discovery of seven X-ray emitting groups of galaxies selected as extended X-ray sources in the 200-ks Chandra coverage of the All-wavelength Extended Groth Strip International Survey (AEGIS). In addition, we report on active galactic nucleus (AGN) activity associated with these systems. For the six extended sources which lie within …
The multi-band non-thermal emission from the supernova remnant RX J1713.7-3946
Zhang, L.; Fang, J.; Zhang, J. F. +2 more
Non-thermal X-rays and very high energy (VHE) γ-rays have been detected from the supernova remnant (SNR) RX J1713.7-3946, and the recent observations with the Suzaku satellite clearly reveal a spectral cut-off in the X-ray spectrum, which directly relates to the cut-off of the energy spectrum of the parent electrons. However, whether the origin of…
New faint optical spectrophotometric standards: hot white dwarfs from the Sloan Digital Sky Survey
Hubeny, Ivan; Allende Prieto, Carlos; Smith, J. Allyn
The spectral energy distributions for pure-hydrogen (DA) hot white dwarfs can be accurately predicted by model atmospheres. This makes it possible to define spectrophotometric calibrators by scaling the theoretical spectral shapes with broad-band photometric observations - a strategy successfully exploited for the spectrographs onboard the Hubble …